This facility prioritizes work in Queues. For help on other methods of prioritizing see:

Normally all Work Items have equal priority in queues (Queues).

The Queue dialog box has a prioritize option. If checked you are given the opportunity to select a label, the value of the label is used to prioritize the Work Items at this Queue. The higher the value of a Work Item's label, the higher its priority (the nearer the front of the queue it will be placed).

Zero is the lowest possible priority (negative values have the same priority as zero). Work items without the selected label are treated a zero priority.

This label (that can have any name) should not be confused with the “priority label”